Linear drive apparatus



July 2, 1968 B. 1.. MCDONALD 3,390,485

LINEAR DRIVE APPARATUS Filed March 3, 1967 BRUCE A. MC DOA/4L0 //Vl/E/V7'OR United States Patent 3,390,435 LINEAR DRIVE APPARATUS Bruce L. McDonald, 544 N. State St., Ann Arbor, Mich. 48104 Filed Mar. 3, 1967, Ser. No. 620,502 7 Claims. (Cl. 49-360) ABSTRACT OF THE DISCLOSURE This disclosure embodies an apparatus which induces a linear movement upon an object, such as a sliding door or window. Power is transmitted from a stream of pressurized gas to the object by means of batfies fastened upon the object. The object moves in a linear manner with respect to the gas outlet in the housing.

This invention relates to apparatus for imparting linear movement to an object, and has particular reference to a device for actuating a sliding door, Window or the like.

An object of the invention is to generally improve mechanisms for opening and closing sliding doors and the like, and to provide a device of that character which is simple in construction, economical to manufacture and efficient in operation.

Another object of the invention is to provide a device of the character indicated which is constructed and arranged to open or close a sliding door or window by the direct application thereto of a stream of pressurized gas.

Another object of the invention is to provide a device of the character indicated which is constructed and arranged so that a door or window may be moved mechanically by a direct application of force, thereby obviating the necessity of using fine precision parts, such as conventional hydraulic or pneumatic cylinders and pistons, or complicated and expansive electrical devices.

Another object of the invention is to provide a device of the character indicated, which has an inherent, positive and reliable safety factor, particularly when employed in an environment of milling human beings, such as in an elevator, subway car, or the like. The safety resides in the fact that the linear movement can be stopped by any predetermined amount of pressure upon the door, without added mechanisms such as a slip-clutch or the like.

The foregoing and other objects and advantages of the invention will become more apparent as the description proceeds, reference being made from time to time to the accompanying drawing, forming part of the within disclosure, in which drawing:

FIG. 1 is a fragmentary, isometric view of a sliding door to which is assembled the device embodying the invention.

FIG. 2 is a vertical section taken substantially on the line 2-2 of FIG. 1.

FIG. 3 is a horizontal section taken substantially on the line 3-3 of FIG. 1.

Referring now more particularly to the drawing it will be understood that in the embodiment herein disclosed, the reference character 7, indicates a sliding door which is to be actuated by the device embodying the invention. Although I have disclosed in the drawing means for moving thedoor 7 only in one direction, it will be understood, however, that the door 7 may be moved in the opposite direction by similar power means, positioned so as to direct the force in the opposite direction, all of which is within the contemplation of the invention. The door 7 also may be spring biased as at -8.

The door 7 is preferably slidably supported by slots 9 and 10 formed in opposite faces of the door, which slots 9 and 10 are arranged to receive the inturned edges 11 and 12 of the housing 13, which has a hollow, substantially cross-shaped cross section, as shown in FIG. 2.

3,390,485 Patented July 2, 1968 "ice The lateral extensions 14 and 15 (FIG. 2) of the housing 13 are respectively arranged to slidably receive therein a series of curved bafiies 16 and 17 which are secured by any suitable means to the opposite sides of the door 7. The baflles 16 and 17 impart motive force to the door 7 as hereinafter described. Each lateral extension 14 and 15 has an intake fitting 18 and 19 (FIG. 3) which communicates with the interior of the housing 13. Each fitting 18 and 19 is connected by a hose 20 and 21 to a larger hose 22, which in turn is connected to a suitable source (not shown) of air or gas under pressure. It will be noted that in operation, with this construction, the pressurized gas, enters the housing 13, on opposite sides of the door 7 striking the baffles 16 and 17 on opposite sides of the door 7 and giving linear force to the door 7. This tends to cushion the door 7 between opposing streams of gas and substantially floats the door on the gas stream, with little or no friction, as the gas bypasses over and under the baffles 16 and 17 into the spaces 23-24 and out the slots 9 and 10 and around the ends and sides of the housing13.

It is believed that the operation of the device is obvious from the foregoing description.

Having described my invention, what I claim and desire to secure by Letters Patent is:

1. A slidable door, an elongated housing having an opening therein for receiving one edge of said door, 'baflies on said door and received in said housing, and means on said housing for directing gas under pressure against said baffles to impart motion to said door.

2. The structure of claim 1, in which said door has slots therein arranged to receive the inturned edges of said housing along said opening, and said baffles are positioned on opposite sides of said door and are spaced from said housing to permit said gas under pressure to flow over and under and around said baffles and out said slots to cushion said door and reduce friction between said door and said housing.

3. The structure of claim 1, in which said housing has the cross section of a hollow cross, the interior of the vertical legs of said cross being arranged to receive one edge of said door and the interior of the horizontal arms of said cross being arranged to receive baffies carried on opposite sides of said door.

4. The structure of claim 1, in which said door has a series of baffles on opposite sides thereof and the means for directing gas under pressure against said bafiies are arranged to direct said gas under pressure in equal volume and pressure to opposite sides of said door simultaneously.

5. The structure of claim 1, in which said door has baffles on either face, and said means for directing gas under pressure are arranged to direct the said gas against said baifles at an angle and in the direction it is desired to move said door.

6. The structure of claim 1, in which said bafiies are curved to form concave elements for receiving the thrust of said gas under pressure.

7. The structure of claim 1, in which said baffles are curved to form concave elements for receiving the thrust of said gas under pressure to move said door in one direction and a spring for biasing said thrust.

References Cited UNITED STATES PATENTS 3/1952 Van de Stigchel 60-57 1/1966 Bobrowski et al 49-360 

